Book Summary

A noted philosopher and member of the Institute for Cognitive and Brain Science examines flaws in current understandings about consciousness while proposing a radical solution that argues that consciousness must not be limited to the confines of the brain.

Note: Book excerpts are provided by the publisher and may contain language some find offensive.

Excerpt: Out Of Our Heads

January 01, 201012:00 AM ET

1 AN ASTONISHING HYPOTHESIS

The human body is the best picture of the human soul.

—Ludwig Wittgenstein

Contemporary research on consciousness in neuroscience rests on unquestioned but highly questionable foundations. Human nature is no less mysterious now than it was a hundred years ago. If we are to understand our human nature, we need to make a fresh start. In this first chapter I lay out the basic challenge.

Consciousness Is Like Money

Stop and notice that you can believe in consciousness—appreciate the fact that we feel and think and that the world shows up for us—without believing that there is a place, or a moment in time, when and where consciousness happens or comes to be inside of us. As a comparison, consider that there's nothing about this piece of paper in my hand, taken in isolation, that makes it one dollar. It would be ludicrous to search for the physical or molecular correlates of its monetary value. The monetary value, after all, is not intrinsic to the piece of paper itself, but depends on the existence of practices and conventions and institutions. The marks or francs or pesos or lire in your wallet didn't change physically when, from one day to the next, they ceased to be legal tender. The change was as real as it gets, but it wasn't a physical change in the money.

Maybe consciousness is like money. Here's a possibility: my consciousness now—with all its particular quality for me now— depends not only on what is happening in my brain but also on my history and my current position in and interaction with the wider world. It is striking that the majority of scientists working on consciousness don't even notice there is an overlooked theoretical possibility here. They tend to think that consciousness, whatever its ultimate explanation, must be something that happens somewhere and sometime in the human brain, just as digestion must take place in the stomach.

According to the now standard view, our conscious lives—the fact that we think and feel and that a world shows up for us—is achieved in us by the action of our brain. The brain produces images of the environment and manipulates those images in a process known as thought. The brain calculates and infers and eventually produces neural commands so that we act. We really are our brains, and our bodies are at most robotic tools at our brains' disposal. The brain is sole author of what is in fact a grand illusion: that we inhabit a richly detailed and meaningful world, that we are the sorts of beings we think we are. What are we, then? If the truth be told, we are brains in vats on life support. Our skulls are the vats and our bodies the life-support systems that keep us going.

Or so mainstream neuroscience, and writers of science fiction, would have it. Is my body a robot that my brain inhabits? Is the world a grand illusion? Is this really an intelligible conception of ourselves?

Are You Your Brain?

The fundamental assumption of much work on the neuroscience of consciousness is that consciousness is, well, a neuroscientific phenomenon. It happens inside us, in the brain.

All scientific theories rest on assumptions. It is important that these assumptions be true. In this book I will try to convince you that this starting assumption of consciousness research is badly mistaken. Consciousness does not happen in the brain. That's why we have been unable to come up with a good explanation of its neural basis.

Francis Crick, the Nobel Prize–winning codiscoverer of the structure of the DNA molecule, has proposed (in a book titled The Astonishing Hypothesis) that "you, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules." With a flourish, he adds, "This hypothesis is so alien to the ideas of most people alive today that it can truly be called astonishing."

What is striking about Crick's hypothesis is how astonishing it isn't. It isn't surprising to be told that there is a thing inside each of us that thinks and feels and wants and decides. This was the view of the seventeenth-century philosopher René Descartes, who held that each of us is identical to an interior something whose essence is consciousness; each of us, really, is an internal res cogitans, or thinking thing. And this is the doctrine promulgated by many religious traditions. Of course, the religions, and Descartes himself, didn't teach that that thing inside us that thinks and feels is a part of our body, a bit of flesh, such as the brain. They supposed that it was something immaterial or spiritual, and so, in that sense, that it was something unnatural. How could mere matter—mere meat—achieve the powers of thought and feeling? Such a possibility boggles the mind. It is precisely on this point, and only on this point, really, that today's neurosci-entist breaks with tradition. As Patricia Churchland, a prominent philosopher of neuroscience, has written: "The weight of evidence now implies that it is the brain, rather than some non-physical stuff, that feels, thinks, decides."

But what needs to be kept clearly in focus is that the neuro-scientists, in updating the traditional conception of ourselves in this way, have really only succeeded in replacing one mystery with another. At present, we have no better understanding of how "a vast assembly of nerve cells and their associated molecules" might give rise to consciousness than we understand how supernatural soul stuff might do the trick. Which is just to say that the you-are-your-brain idea is not so much a working hypothesis as it is the placeholder for one.

Consciousness researchers in neuroscience like to think that they have broken with philosophy. They have left it behind and set off on the path of science. As Crick has written: "No longer need one spend time attempting . . . to endure the tedium of philosophers perpetually disagreeing with each other. Consciousness is now largely a scientific problem."

Crick is right that the problem of consciousness is now a problem for science. But this doesn't mean that it is no longer a problem for philosophy. For one thing, the aims of philosophy and of science are not different: to achieve understanding of the problems that matter to us. But that's just the beginning: it is a mistake to think that the new neuroscience of consciousness has broken with philosophy or moved beyond it. In fact, as we have been discovering, Crick and other neuroscientists have simply taken a specific family of philosophical assumptions for granted, so much so that their own reliance on them has become all but invisible to themselves. But the fact of the reliance is everywhere in evidence. Its perturbing influence is felt in the seeming mandatoriness of what we can think of as a kind of "gastric juices" conception of consciousness—that is, the idea that consciousness happens in the head the way digestion happens in the stomach. I mentioned before that it is overoptimistic to think of the new neuroscience of consciousness as in its infancy. Devel-opmentally, it would be more apt to characterize it as like a teenager. Like teenagers, neuroscience is in the grip of technology; it has a grandiose sense of its own abilities; and it is entirely lacking a sense of the history of what, for it, seems so new and exciting.

A Really Astonishing Hypothesis

It would be astonishing to learn that you are not your brain. All the more so to be told that the brain is not the thing inside of you that makes you conscious because, in fact, there is no thing inside of you that makes you conscious. It would then turn out that contemporary neuroscience has been in the thrall of a false dichotomy, as if the only alternative to the idea that the thing inside you that thinks and feels is immaterial and supernatural is the idea that the thing inside you that thinks and feels is a bit of your body. It would be astonishing to be told that we've been thinking about consciousness the wrong way—as something that happens in us, like digestion—when we should be thinking about it as something we do, as a kind of living activity.

In this book I advance this truly astonishing hypothesis: to understand consciousness in humans and animals, we must look not inward, into the recesses of our insides; rather, we need to look to the ways in which each of us, as a whole animal, carries on the processes of living in and with and in response to the world around us. The subject of experience is not a bit of your body. You are not your brain. The brain, rather, is part of what you are.

A Note on Terminology, and the Thesis Restated

In this book I use the term "consciousness" to mean, roughly, experience. And I think of experience, broadly, as encompassing thinking, feeling, and the fact that a world "shows up" for us in perception. Many writers have sought to define terms more narrowly than this. No doubt there are important distinctions that can and, for certain purposes at least, should be drawn. For example, a contrast is often made between thought or cognition, on the one hand, and sensation and feeling, or phenomenal experience, on the other. The contrast is between planning and carrying out an action, for example, and, say, experiencing the taste of licorice. When people draw this distinction it is usually because they think it is much easier to explain thought, say, than it is to explain the quality of our conscious episodes. For example, many theorists hold that thinking is a matter of computation and that we shed light on how brains think by comparing them with computers. As I discuss in Chapter 7, it is far from true that computers can think; moreover, I argue there, computers can't think largely for the same reason that brains can't. Meaningful thought arises only for the whole animal dynamically engaged with its environment, or so I contend. And indeed the same is true for the quality of our conscious episodes. The taste of licorice is not something that happens in our brains (although it is true that when we eat licorice, we do so by putting it in our mouths).

Conscious states are typically states that I can talk about, that influence what I do, and so they are states that I can make use of in planning. For example, my dislike of the taste of licorice is something that informs my larger cognitive and behavioral life. Among other things, it will influence my shopping behavior. Such a state is available or accessible to thought and talk; it is sometimes said that this marks a distinctive sort of consciousness that the philosopher Ned Block has named access consciousness. The access consciousness of my feelings about licorice is one thing, however, and the experience of the licorice itself is another. The latter is an episode in what Block has called phenomenal consciousness, and the question of whether an episode is phenomenally conscious is, or so it seems, altogether different from the question of whether it is access conscious. To ask whether an episode is phenomenally conscious is to ask, in the philosopher Thomas Nagel's phrase, whether "there is something it is like to be" in that state. To ask whether it is access conscious is to ask whether the occurrence of the state influences what we say and do and want and plan and so on.

Other distinctions abound. To be conscious, as opposed to being unconscious, is to be awake, aroused, alert, as opposed to being asleep or knocked out. In ordinary language, self-consciousness means a kind of interfering attentiveness to how others view oneself. In philosophy and cognitive science, self-consciousness means something different. Self-consciousness is that feature of experience by virtue of which our experiences are ours. Experiences have a kind of "mine"-ness that makes them, distinctively, our own, or so some thinkers have maintained. Freud famously hypothesized the importance of unconscious desires and wishes in explaining human psychology.

Distinctions are useful, depending on your purposes. For my purposes, these distinctions don't matter in particular. When they do, I'll try to be careful to be clear about what I am referring to. The problem of consciousness, as I am thinking of it here, is that of understanding our nature as beings who think, who feel, and for whom a world shows up.

Another terminological issue arises in connection with the words "mind" and "brain." The latter refers to a part of the body found in the head and connected up to a larger system known as the nervous system. It is widely believed that the brain and the larger nervous system of which it is a part play a special role in explaining our powers of mind (e.g., thought, memory, perception, emotion, and the like). Indeed, some scientists and philosophers think that the mind is the brain. Be that as it may, it is important to realize that no one holds that the concept of brain and the concept of mind are the same. To have a mind is, roughly, in my sense, to be conscious—that is, to have experience and to be capable of thought, feeling, planning, etc. To have a brain, on the other hand, is to have a certain kind of bodily organ or part. Ordinary language is sometimes a bit confused about this, so we need to be careful. Being intelligent, for example, is said to be a matter of having brains.

My central claim in this book is that to understand conscious-ness—the fact that we think and feel and that a world shows up for us—we need to look at a larger system of which the brain is only one element. Consciousness is not something the brain achieves on its own. Consciousness requires the joint operation of brain, body, and world. Indeed, consciousness is an achievement of the whole animal in its environmental context. I deny, in short, that you are your brain. But I don't deny that you have a brain. And I certainly don't deny that you have a mind. To have a mind, though, requires more than a brain. Brains don't have minds; people (and other animals) do.

The Man with Two Brains

I have always been a fan of Carl Reiner's hilarious movie The Man with Two Brains. Steve Martin plays the lead role, a brain surgeon named Dr. Hfuhruhurr who falls in love with a disembodied brain awaiting a transplant. This is the brain of the woman of his dreams. Now all he needs—all she needs—is a body! He sets about a villainous scheme to get his hands on the body of the beautiful and svelte Dolores Benedict (played by Kathleen Turner). The joke is that, unbeknownst to him, the self whose brain he loves has an eating disorder. By the time she recovers from the brain transplant, she's morbidly and unattractively obese. (He loves her anyway!)

This is the stuff of science fiction. Pretty far-fetched, to be sure. The fact that we find it at all comprehensible, let alone compelling, shows that the "astonishing hypothesis" of the establishment neuroscientist now belongs to the conventional wisdom of the culture at large. We think of ourselves—or find it easy to take seriously the idea of ourselves—as dependent on our brains in a special sort of way, very different from the way we depend on our hearts, say. You gotta have heart, yes. But it is the brain, with its distinctive neuronal snap, crackle, and pop, that is our ground. We inhere in our brains. What makes us the kind of thing we are—beings who can feel and reason and think and see—is accomplished in our bodies by our brains.

I ask again: Is this a plausible conception of ourselves? Reiner's movie casts an interesting light on this question. The film itself needs to present us with communication between the Martin character and his beloved brain-in-a-cookie-jar. But how can it do this? How, for example, to capture the fact that the lovely female voice Martin hears—what we in the audience experience as a voice-over—is actually the voice of the person in that brain-in-a-cookie-jar? Film normally trades on the ventriloquist effect. We hear the voice coming from the mouth because we see the mouth move in synchrony with just those words. Vision captures and directs what we hear. In fact, this is an important part of normal speech perception. The problem with a speaking brain is that it has no mouth. What ties the sounds to the brain? What makes them its words? The movie strikes on a silly but funny solution. The brain glows and pulsates in synchrony with its spoken words. What makes this solution interesting, as well as silly and funny, is that, in a way, it's cheating. Brains don't pulsate or change colors, and by introducing this feature you are, in effect, giving the brain a body or, more important, a face (what the brain is supposed to lack). And maybe that's not just a somewhat confused filmic conceit but something of a conceptual necessity. It's hard even to conceive of a consciousness that lacks a face. That's why, tragically, even friends and family find it difficult to empathize with Parkinson's patients whose faces have grown masklike. And that's why, in a love scene in The Man with Two Brains, the Steve Martin character puts a scarf around the base of his love's brain-in-a-cookie-jar, a hat on top, and bright red candy-wax lips on the front. Wittgenstein wrote that it is only of what looks and behaves like a person that we say it sees, thinks, feels. The problem with a brain is that it doesn't look and behave like a person.

Consciousness in a Petri Dish?

If the new neuroscience establishment is right, then it ought to be possible, at least in principle, to have consciousness in a petri dish. All that would be required for consciousness in a petri dish is that the cells be wired up to each other and stimulated in a suitable matter.

My own view is that the suggestion that cells in a dish could be conscious—or that you could have a conscious brain in a vat—is absurd; it's time to overhaul our starting assumptions about what consciousness is if they lead us to such a conclusion.